A landmark genetic study has pinpointed biological drivers of cocaine use disorder that extend well beyond the brain, raising fresh hopes for treatments tailored to an individual’s genetic profile.

Researchers at the University of California San Diego used more than 800 genetically diverse rats to map the DNA signatures linked to cocaine use disorder, producing what is now the largest genetic experiment of cocaine self-administration ever conducted in an animal model. The findings, which show strong overlap with human genetic data, suggest that the body’s ability to process cocaine may be just as important as what happens in the brain.

Six Genetic Hotspots Identified

The research team measured a range of addiction-relevant behaviours, including how quickly animals learnt to self-administer cocaine, how their intake escalated over time, and the compulsiveness of their drug-seeking. Of all the traits measured, all but three showed clear genetic influences. Heritability estimates ranged from 7% to 16%, confirming that cocaine use disorder carries a meaningful inherited component.

Using millions of genetic markers, the team identified six significant regions of DNA consistently tied to addictive behaviour. The most striking finding centred on chromosome 19, where a cluster of carboxylesterase genes, specifically Ces1c and Ces1d, appeared tightly linked to how frequently the animals took cocaine.

Carboxylesterases are liver enzymes responsible for breaking down cocaine in the body. Their identification as a genetic influence on cocaine use disorder was, in the words of co-corresponding author Professor Olivier George of UC San Diego School of Medicine, “a real ‘aha’ moment.” He added: “It reminds us that addiction is not only in the brain. It is a complex puzzle involving how the entire body processes the drug.”

Shared Architecture Across Substances

The other five genetic regions identified were equally revealing. The gene Trak2 had previously been linked to cocaine use disorder in humans. Three further genes, Slc10a7, Plcl1, and Satb2, have established associations with alcohol and tobacco use disorders.

The overlap across these substances points to a shared genetic architecture underlying addiction behaviours more broadly. This convergence matters. It suggests that the biological vulnerability underlying cocaine use disorder is not isolated; it connects to wider patterns of substance dependence that researchers and clinicians are still working to understand.

A Body-Wide Problem

The study’s findings challenge a narrow view of cocaine use disorder as purely a brain disease. While the brain remains central to the cycle of craving and compulsion, the liver’s role in metabolising cocaine now appears to shape how addictive the drug becomes for any given individual.

Carboxylesterase enzymes are considered “druggable,” meaning it may be possible to develop medicines that alter how efficiently the body breaks down cocaine. By modifying the drug’s metabolic pathway, such treatments could reduce the physiological reinforcement that drives continued use. That is a meaningful shift in how researchers are thinking about pharmacological approaches to cocaine dependence.

The results also align with findings from human genome-wide association studies, lending the animal model data considerable credibility. Broad concordance between rat genetic data and human GWAS results strengthens the case for translating these discoveries into clinical research.

Precision Medicine on the Horizon

The implications for treatment design are significant. Cocaine use disorder currently has no approved pharmacotherapy, leaving clinicians with limited options. Identifying genetic variants that influence how individuals metabolise and respond to cocaine opens a path towards precision medicine approaches, where treatment decisions are guided by a patient’s specific genetic profile rather than a one-size-fits-all protocol.

The next step for the research team is to understand exactly how the identified genetic variants alter enzyme function. That work will determine whether modifying carboxylesterase activity is a viable clinical strategy and which patients might benefit most.

Addiction is not a failure of character. This study adds to a growing body of evidence that cocaine use disorder has deep biological roots, shaped by genetics, metabolism, and the full physiology of the body. Understanding those roots is essential to building a more effective response.

Source: dbrecoveryresources